Hip abduction is primarily mediated by which nerve roots via the Gluteus medius and minimus?

• A. L2, L3
• B. S1
• C. L4, L5, S1
• D. L2, L3, L4

Answer: (C)

Hip abduction is carried out by the gluteus medius and minimus, which stabilize the pelvis during single-leg stance. These muscles are innervated by the superior gluteal nerve, and the nerve roots that contribute to this nerve are L4, L5 and S1. So the nerve root combination most relevant for this action is L4, L5, and S1. The other options don’t fit because they either miss part of the L4–S1 contribution (S1 alone) or point to different muscle groups (L2–L3 are more associated with hip flexors via the femoral nerve, and L2–L4 would be incomplete for the superior gluteal nerve). Clinically, injury to this nerve can cause a Trendelenburg gait due to inability to abduct the hip and keep the pelvis level.